The present invention relates to a low-frequency sound reproducing speaker apparatus of Kelton type connected to a vehicle mounted acoustic system as a subwoofer.
In recent years, demand of a vehicle mounted acoustic system constructed by a constitution of mounting a subwoofer with an object of reproducing heavy low-frequency sound is increased in accordance with spreading or the like of a theater system for vehicle mounted use.
In a background art, there have been proposed various kinds of subwoofers constructed by a constitution of containing a woofer unit having a large aperture in a large-sized hermetically closed cabinet and in a case of vehicle mounted use, assigned to a trunk room of a vehicle as a large-sized hermetically closed cabinet.
However, according to the constitution, by occupying the trunk room by the subwoofer, a luggage room space is not present and accommodation performance of the vehicle is significantly deteriorated.
Hence, in the case of the subwoofer for vehicle mounted use, small-sized formation poses an important problem and there have been proposed a subwoofer constituted by Kelton type suitable for high quality reproducing of low-frequency sound even by a cabinet having a small capacity and integrated to an arm rest of a seat (refer to, for example, JP-A-5-276588 and JP-A-6-122347), a woofer mounted on a seat cushion (seat portion) of a rear seat (refer to, for example, JP-A-2004-330951) and the like.